Effects of bleeding of Actinidia arguta (Sieb. & Zucc) Planch. ex miq. on its plant growth, physiological characteristics and fruit quality

Abstract

Bleeding is as particularly a serious phenomenon in Actinidia arguta and has important effects on this plant's growth and development. Here we used A. arguta to study the effects of bleeding on the growth and development of leaves and fruits after a bleeding episode. We detect and analyze physiological indices of leaves and fruit after bleeding. The result revealed that the relative electrical conductivity and malondialdehyde (MDA) of leaves increased in treatment. Nitro blue tetrazolium chloride (NBT) and 3,3-diaminobenzidine (DAB) staining revealed the accumulation of reactive oxygen species (ROS) in leaves after bleeding. The chlorophyll content and photosynthetic parameter of plants were also decreased. In fruits, pulp and seed water content decreased after the damage, as did fruit vitamin C (Vc), soluble sugar content, and soluble solids content (SSC); the titratable acid content did not change significantly. We therefore conclude that bleeding affects the physiological indices of A. arguta. Our study provides a theoretical basis for understanding the physiological changes of A. arguta after bleeding episodes and laying a timely foundation for advancing research on A. arguta bleeding and long-term field studies should be executed in order to gain insights into underlying mechanisms.

Keywords: Actinidia arguta Sieb. & Zucc. Planch. ex Miq.; Bleeding; Fruit quality; Physiological characteristics.

Fig. 1

The anatomical structure of main veins of leaves Note: A-D: Control group; E-H: Treatment group; Xy: Xylem; Pc: Parenchyma cell; CZ: Cambium zone; Ph: Phloem; Pi: Pith; Co: Collenchyma; Pt: palisade tissue; St: Sponge tissue; Magnification: 100 times; Bar = 100 μm

Fig. 2

The effects of bleeding on leaves morphology and growth parameters in different phenological stages Note: A: a, c, e, g: Control group; b, d, f, h: Treatment group B: Leaf length; C: Leaf width; D: Petiole long; E: Petiole width; F: The longest leaf; G: Leaf area; Bar = 10 cm; Different letters indicate significant differences (P < 0.05)

Fig. 3

The effects of bleeding treatment on relative conductivity (A), relative water content (B) and malondialdehyde (MDA) content (C) of leaves at different phenological stages Note: A: Relative conductivity; B: Relative moisture content; C: Malondialdehyde; Different letters indicate significant differences (P < 0.05)

Fig. 4

The effect of bleeding treatment on chlorophyll at different phenological periods Note: A: Chlorophyll a; b: Chlorophyll b; C: Chlorophyll a/b; D: Carotenoids; Different letters indicate significant differences (P < 0.05)

Fig. 5

The effect of bleeding treatment on photosynthetic parameters of leaves in different phenological periods Note: A: The net photosynthetic rate (Pn); B: Intercellular CO₂ concentration (Ci); C: Stomatal conductance (Gs); D: Transpiration rate (Tr); Different letters indicate significant differences (P < 0.05)

Fig. 6

The effect of bleeding on DAB and NBT staining of leaves Note: A, C, E, G: DAB staining; B, D, F, H: NBT staining; Bar = 5 cm

Fig. 7

The fruit phenotypic image, phenotypic index and fruit quality during fruit ripening under bleeding condition Note: A: (a, c): Control group; (b, d): Treatment group; B: The 100-grain weight and single fruit weight; C: Seed water content and pulp water content; D: Vitamin C and soluble sugar; E: Titratable acid and soluble solids content (SSC); Bar = 5 cm; Different letters indicate significant differences (P < 0.05)